The present invention relates to a valve. More particularly this invention concerns an actuating assembly or control knob for a valve whose rotation is normally limited but where the rotation limit can be overridden.
A standard valve-actuating assembly is described in European 0,232,454. The valve has a housing from which projects a stem rotatable about an axis. The actuating assembly comprises an abutment ring fixed on the housing, formed with an annular slot, and having an abutment projecting radially outward into the slot. A knob mounted on and rotatable with the stem adjacent the ring carries another abutment which normally rides in the slot and which can be deflected outward to clear the abutment in the slot. When the knob abutment is not moved, the two abutments limit the angular travel of the knob and therefore the temperature or volume of water outputted by the valve. The abutment is formed as a first-class or two-arm lever which requires that the entire knob assembly be axially rather long, something that is often quite undesirable from a design point of view.
It is therefore an object of the present invention to provide an improved valve-actuating assembly.
Another object is the provision of such an improved valve-actuating assembly which overcomes the above-given disadvantages, that is which is extremely simple and compact, yet inexpensive and simple to manufacture.
A valve having a housing from which projects a stem rotatable about an axis has an actuating assembly with according to the invention an abutment ring fixed on the housing, formed with an annular slot, and having an abutment projecting radially into the slot. A knob mounted on and rotatable with the stem adjacent the ring carries a single-arm abutment lever pivoted on the knob and having an end engaged in the slot and displaceable radially between a radial outer position angularly engageable with the abutment and a radial inner position so that when the end is in the outer position rotation of the knob is blocked by engagement of the lever end and the abutment. A spring braced between the knob and lever urges the end into the outer position. A radially displaceable button on the knob engageable with the lever is radially inwardly displaceable to move the lever into its inner position.
With this system the abutment lever is a third-class lever with the fulcrum at one end, the load formed by the end that contacts the ring abutment at the opposite end, and the force applied by the button in the middle. Accordingly the structure can be made quite compact and short to allow the assembly to be incorporated in an attractive valve.
The abutment lever according to the invention can be unitarily formed with the button. It can be formed with a radially inwardly open blind bore holding a compression spring seated in the bore and radially inwardly engaging the knob.
In another system the lever arm has another end seated in the knob and is elastically deformable so that the lever arm forms the spring. Such a structure is extremely simple, durable, and inexpensive to manufacture.
The knob in accordance with the invention is formed with a diametral cutout and is provided in the diametral cutout with a crosspiece having an end forming an opening through which the button projects. The abutment lever is mounted on the crosspiece. In this system the abutment lever can be unitarily formed with the button or the lever arm can have another end seated in the crosspiece and be elastically deformable so that the lever arm forms the spring as described above.
Normally according to the invention the button has a body formed with tangentially extending pivot pins seated in the crosspiece. The body has formations such as barbed gripper noses engaging and fitting with the lever arm. In addition the crosspiece is formed with axially open snap seats in which the pivot pins are engaged. In this system the spring can have a coil body with one leg bearing against the crosspiece and another leg bearing against the abutment. The abutment has an outer face bearing on the knob in the outer position. The crosspiece has elastically deformable mounting tongues engaging the knob and securing the crosspiece thereon and the stem engages the tongues and locks them to the knob when the knob is mounted on the stem.